The present invention relates to a method and apparatus for operating a metallurgical blast furnace or, more precisely, to continuously determine the profile of the charge at the mouth of the blast furnace.
As is known the operation of a metallurgical blast furnace depends especially on the gaseous distribution in the interior of the charge.
It is likewise known that this distribution depends essentially on the manner of regulating the charge of the material which is performed in modern blast furnaces especially equipped with impact rings of variable geometry or with movable charging chutes, which constitute means to regulate the charge. However, experience has shown that it is difficult to foresee precisely, even with the help of models or mock-ups the way the charge proceeds, that is the profile and local thickness of successive layers of the charge or the speed at which the latter descends. For this purpose it seems therefore essential to be able to determine "in situ" the profile of the charge at the mouth of the blast furnace.
Various attempts have already been made to solve this problem. For instance, there is known an arrangement with a mechanical probe, or a system for triangulation by means of gamma rays, or a luminous beam sweeping the surface of the charge.
Mechanical probes which are vertically lowered up to the surface of the charge present, however, certain inconveniences. Especially, it is only possible to obtain punctual measurements separated in time and space from each other. In addition, the automatization of such a probe is not at all easy and requires considerable maintenance cost.
On the other hand, the method using gamma rays cause especially difficulties of placing a radioactive source at the point of utilization.
The optical methods appear in principal the most satisfactory methods since they are inoffensive and since they permit a continuous functioning. Furthermore, it is possible to install all the necessary material for carrying out the method at the exterior of the blast furnace, which facilitates the maintenance.
Nevertheless, these methods seem up to now not to have been developed in a manner as could be expected. As far as applicant knows only some tentative methods have been developed, which are based in particular on the determination of the length of the incident beam, which presents certain inconveniences, such as the necessity of treating the received signal while taking into consideration the position of the emitter and the direction of the incident beam.